A federal official said lack of funding and availability of specialized personnel have delayed efforts to rid Lehua Island near Ni'ihau of Polynesian rats.

U.S. Fish and Wildlife Service spokesman Ken Foote estimated the job will cost between $200,000 and $700,000. He said rats attack, damage and kill native and endangered plants and animals on Lehua.

The uninhabited 290-acre island is situated less than a mile north of Ni'ihau.

Foote said state and federal officials are seeking the necessary funding and personnel to conduct a reassessment of the rat population of the island.

He estimated such a reassessment visit might be accomplished within the next two months.

Hunting was used to remove rabbits from Lehua in 2005-06. They were considered a threat to plants.